The present invention relates to a pearly-lustered container suitable for use with cosmetics or the like.
A conventional pearly-lustered container of this kind is proposed, for example, in Japanese Patent Publication No. 41596/78, according to which the container body has a double-layer structure composed of an outer layer of a transparent synthetic resinous material mixed with a predetermined amount of pearly essence and an inner layer of an opaque synthetic resinous material colored in a desired color. It is described in this prior art literature that, with such a structure, since rays of light incident on the container are diffuse-reflected by pearl essence particles mixed in the transparent resin of the outer layer, the container surface assumes a pearly luster, and that when the outer layer is sufficiently thick, light reflected from the neighborhood of the outer layer surface and light diffuse-reflected by the pearl essence particles distributed throughout the outer layer are superimposed on each other to add a cubic effect to the appearance of the container. In practice, however, containers of this prior art arrangement, now on the market, have their outer and inner layers both formed of polyethylene resin to a thickness of about 250 microns. The polyethylene resin is very economical and the most practical resin but has poor transparency. Therefore, as the thickness of the layer increases, its light transmission efficiency gradually decreases, finally resulting in the layer becoming almost semitransaprent. Accordingly, an increase in the thickness of the outer layer permits an increase in the amount of pearl essence mixed in the layer but, in this case, although the reflectivity of incident light which is reflected by the pearl essence particles present near the surface of the outer layer is high, the reflectivity by the pearl essence particles deep in the outer layer in the vicinity of the inner layer is impaired by the low transparency of the polylethylene resin. Furthermore, in order to make the container attractive in appearance, the opaque inner layer is colored by using a coloring pigment so that coloring agent particles may be seen through the outer layer. Accordingly, an increase in the amount of pearl essence mixed for heightening the pearly luster impairs the light transparency of the outer layer. Thus, the amount of pearl essence mixed in the outer layer is also limited.
With such a conventional pearly-lustered container as described above, a decrease in the amount of pearl essence employed decreases the quantity of light reflected by the pearl essence particles and, in addition, only the pearl essence particles in the vicinity of the surface of the outer layer contribute to radiation of the pearly luster, and the pearl essence particles deep in the outer layer do not much contribute to it. Moreover, mixing of the pearl essence which does not much contribute to radiation of the pearly luster is economically disadvantageous because the pearl essence itself is expensive.